BQ3285ESS - English Editing Encyclopedia Entry

Product Overview

Category: Integrated Circuit (IC)

Use: Real-Time Clock (RTC) and Calendar

Characteristics: - Low-power consumption - High accuracy - Non-volatile memory for data storage - I2C interface for communication - Automatic power-fail detection and switch-over circuitry

Package: Small Outline Integrated Circuit (SOIC)

Essence: The BQ3285ESS is a real-time clock and calendar IC designed to provide accurate timekeeping in various electronic devices.

Packaging/Quantity: Available in tape and reel packaging, with 250 units per reel.

Specifications

• Supply Voltage: 2.7V to 5.5V
• Timekeeping Accuracy: ±2 minutes per month at 25°C
• Operating Temperature Range: -40°C to +85°C
• Battery Backup Voltage: 1.8V to 3.6V
• I2C Bus Frequency: Up to 400kHz
• Memory Size: 256 bytes of non-volatile RAM

Detailed Pin Configuration

The BQ3285ESS IC has a total of 16 pins. The pin configuration is as follows:

1. VCC - Power supply voltage input
2. GND - Ground reference
3. SDA - Serial Data Line for I2C communication
4. SCL - Serial Clock Line for I2C communication
5. X1 - Crystal oscillator input
6. X2 - Crystal oscillator output
7. VBAT - Battery backup voltage input
8. VBATGND - Battery backup ground reference
9. IRQ - Interrupt Request output
10. SQW - Square Wave output
11. TEST - Test mode input
12. OSCOUT - Oscillator output
13. AD0 - Address bit 0 input
14. AD1 - Address bit 1 input
15. AD2 - Address bit 2 input
16. VCC2 - Power supply voltage input for backup battery

Functional Features

1. Real-Time Clock: Provides accurate timekeeping with a built-in oscillator and crystal.
2. Calendar Function: Tracks the date, month, and year, including leap years.
3. Battery Backup: Maintains timekeeping during power loss using an external backup battery.
4. I2C Interface: Allows communication with other devices using the I2C protocol.
5. Automatic Power-Fail Detection: Detects power loss and switches to backup power automatically.
6. Interrupt Output: Generates an interrupt signal to notify the system of specific events.
7. Square Wave Output: Generates a square wave signal with programmable frequency.

Advantages and Disadvantages

Advantages: - Low-power consumption extends battery life. - High accuracy ensures precise timekeeping. - Non-volatile memory retains data during power loss. - I2C interface enables easy integration with other devices. - Automatic power-fail detection provides reliable operation.

Disadvantages: - Limited memory size may restrict the storage of additional data. - Requires an external backup battery for uninterrupted timekeeping during power loss.

Working Principles

The BQ3285ESS utilizes an internal oscillator and a crystal to generate clock signals for timekeeping. It communicates with the host system through the I2C interface, allowing the system to read and write time and date information. The IC also monitors the power supply voltage and automatically switches to the backup battery when a power failure is detected. This ensures continuous timekeeping even during power outages.

Detailed Application Field Plans

The BQ3285ESS is commonly used in various electronic devices that require accurate timekeeping and calendar functionality. Some application fields include:

1. Consumer Electronics: Used in digital watches, alarm clocks, and electronic calendars.
2. Industrial Automation: Integrated into programmable logic controllers (PLCs) for time-based operations.
3. Automotive Systems: Incorporated into car dashboards for clock display and event scheduling.
4. Medical Devices: Utilized in medical equipment that requires precise time synchronization.
5. Communication Equipment: Integrated into network devices for accurate time stamping of data packets.

Detailed and Complete Alternative Models

1. DS3231 - Real-Time Clock IC with temperature compensation and additional alarms.
2. PCF8563 - Real-Time Clock and Calendar IC with I2C interface and battery backup.
3. MCP7940N - Low-power Real-Time Clock IC with battery switchover and SRAM memory.

These alternative models offer similar functionality to the BQ3285ESS and can be considered as alternatives based on specific requirements.

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